1. Field of the Invention
The present invention relates to a paper sheet stacking mechanism, and more particularly to a paper sheet stacking mechanism for a partitioned box to classify mail by destination in a mail sorting system.
2. Description of the Related Art
Before turning to the present invention it is deemed advantageous to briefly discuss known paper sheet stacking mechanisms with reference to FIGS. 1 and 2.
FIG. 1 shows a paper sheet tracking mechanism. A guide plate 101 is fixed to a top plate 102 of a stacking box 100 to guide deposited sheets 103 toward the bottom of the stacking box 100 installed with an inclination in the direction in which the sheets 103 are to be carried.
However, in this sheet stacking mechanism whose guide plate 101 is fixed to the top plate 102 of the stacking box 100, since the sheets 103 can be stacked no farther than the position of the bottom end of the guide plate 101, it is limited to stack the sheets 103 from bottom of the stacking box 100 to the bottom end of the guide plate 101, resulting in the problem of a correspondingly reduced stacking capacity.
Means to solve this problem is disclosed in the Gazette of Patent Disclosure No. 1988-143172. In this means, as illustrated in FIG. 2, in order to guide deposited sheets 203 toward the bottom of a stacking box 200 installed with an inclination in the direction in which the sheets 203 are to be carried, a guide plate 202 is fitted swingably to a fixed guide plate 201 fixed to the top plate 204 of the stacking box 200.
The sheets 203, as they are carried, are guided by the fixed guide plate 201 and the guide plate 202 to be stacked on the bottom of the stacking box 200. When the stacked volume of the sheets 203 exceeds a prescribed level, the swingable guide plate 202 is pressed upward.
However, in this stacking mechanism disclosed in the Gazette of Patent Disclosure No. 1988-143172, although the stacking capacity is not reduced because the guide plate 202 is pressed upward according to the volume of stacked sheets 203, there is the problem of inability to reliably guide the sheets when relatively heavy sheets are deposited into the stacking box 200, which would let the guide plate flip up.